Radiation oncology practitioners and researchers have developed various devices, systems and methods, each typically being designed for a specific diseased body organ or part and/or for one or more treatment regimens. Whether the treatment regimen is a one-step or multi-step protocol, it is important to maintain a good balance among radiation dosage, placement and timing. Timing can involve treatment and non-treatment intervals that vary depending upon the oncology protocol to be followed.
Carcinoma and sarcoma treatment procedures can follow a protocol calling for a series of multiple applications, such as when following high dose rate (HDR) brachytherapy. At times, the radiation oncologist may choose to use a low dose rate (LDR) regimen, typically based on cesium delivery as 137Cs. For HDR regimens 192Ir is frequently used because of its high specific activity. Other isotopes are available and used as warranted. The degree of treatment is measured in terms of units of radiation exposure (in roentgens or Gray or Gy), and often these are prescribed at specific points. Details in this regard are known to radiation oncologists, medical physicists and other medical professionals experienced in the art. An objective often is to provide reasonably constant and predictable dose rates at each location at which the isotopes are applied.
Sarcomas are types of cancer that develop from certain tissues, usually bone or muscle. Bone sarcomas are generally thought of as bone cancer. Soft tissue sarcomas develop from soft tissues such as fat, muscle, nerves, fibrous tissues, blood vessels, deep skin, cartilage, and hematopoietic tissues. For example, osteosarcoma arises from bone, chondrosarcoma arises from cartilage, liposarcoma arises from fat, and leiomyosarcoma arises from smooth muscle. Some sarcomas are evident, being on skin surface, while others are internal and require surgical procedures to access the sarcoma for surgery, radiation therapy or a combination thereof. Efforts have been made to advance targeted therapy treatment.
Sarcoma cancers can be found in any part of the body, although many of them develop in arms or legs. Less commonly, sarcomas also can be found in the trunk, head and neck area. Sarcomas are also experienced with internal organs and areas in the back of the abdominal cavity.
Radiation therapy for soft tissue sarcomas can be addressed with external beam radiation therapy or brachytherapy. In external beam radiation therapy, radiation is delivered from outside the body and focused on the cancer, and this is typical radiation therapy applied to treat sarcomas. These can include intensity modulated radiation therapy (IMRT) and proton beam radiation. Brachytherapy or internal radiation therapy places small pellets or seeds of radioactive material in or near the cancer. Traditionally, for soft tissue sarcoma, the pellets or seeds are put into catheters that have been placed during surgery. Because of side effects, it is important that radiation therapy proceed with precision, including enhanced assurance of proper placement with respect to the cancerous site, whether relatively small or larger. At times, sarcomas cover a relatively large surface area.
Accordingly, it is clear that body surface radiation treatment and other treatments such as those gaining access through a surgical opening or access location, need to be exacting and specific in each of dose rates, durations and radiation target locations, for example. In addition, the closeness of tissue not intended to be irradiated should be taken into consideration. For example, the present disclosure has come to recognize that the radiation oncologist may find it useful to have adequate direct control in isotope placement to generate a radiation treatment plan specific for this placement and for the particular anatomy and disease location and severity for the particular patient and for the treatment event at hand.
It will be appreciated that radiation delivery systems can be used in treatments that are applied manually or remotely using remote afterloading systems. In remote afterloading systems, the radioactive materials are delivered from a source by way of hollow tubes to hollow treatment portions or locations. Radioactive material can be in the form of wires, seeds, fluids or other forms.